Patients with SLE have anti-T-cell antibodies and loss of a subpopulation of T cells. This subpopulation regulates B cell activity. In the absence of adequate regulatory function, excessive antibody forming cells are found. These cells have specificity for a variety of chemical haptens rather than just auto-antigens. Excessive B cell activity and loss of regulatory cells occurs in patients with active SLE, and is often normal in SLE patients in remission. Loss of both helper T cells and suppressor T cells may occur in patients with active SLE. BIBLIOGRAPHIC REFERENCES: Budman, D.R. and Steinberg, A.D.: Current concepts of the hematologic aspects of systemic lupus erythematosus. Ann. Intern. Med. 86:220-229, 1977. Budman, D.R., Merchant, E.B., Steinberg, A.D., Doft, B., Gershwin, M. E., Lizzio, E. and Reeves, J.P.: Increased spontaneous activity of antibody forming cells in the peripheral blood of patients with active systemic lupus erythematosus. Arth. Rheum. 20:829-833, 1977.